What this tasker does is when you get out of your car Tasker times stamps what time you leave and also your location, when you want to find the car you push a button and the nav opens taking you back to your car.
The only thing is you need a bluetooth stereo connection or hands free
Profile "Car Set"
Condition bluetooth with the name "Million" connected Million is the name of my car stereo
Actions on condition connected
1 Secure Settings "Pattern Lock Disabled" (this is only used if your phone is rooted and you have secure settings app)
2 Set wallpaper (browse to your image you want to use in the car)
3 Start your music player if you want to
3 Notification Popup "Bluetooth Connected"

ACTIONS ON CONDITION EXIT
1 Set variable %PARKEDTIME to %TIME
2 Set Minimalistic Text variable 'parkedtime' to %PARKEDTIME see below for more info
3 Variable set %PARKED to %LOCN If %PARKED !Set
4 Clear variable %PARKED (which will hold the car's parked location)
5 Get GPS location with 240 second timeout
6 Set variable %PARKED to %LOC (GPS location)
7 Set variable %PARKED to %LOCN (Network location) if variable %PARKED is not set (i.e. GPS did not get a fix)
8 Popup text "bluetooth disconnected"

TASK-FIND CAR
New task setup called "Go Car" give it an icon like say a house
1 Open Map
Mode Navigate To
Address %PARKED
Now save it
now activate a widget on your phone and choose tasker and task "Go Car"
save and back out
if you now push the home widget it should open your nav software and take you back to your car

Minimalist text widget (doing this from memory so may be a little different)
Download this from the market
make another widget
choose hor 2*1 a black screen will pop up give it a name of your choice
click predefined layout and choose custom
click custom layout and another screen pops up with things like hour minute etc
push and hold each grey icon and drag it to the bin
click the green button to the right
on the menu that pops up choose misc
then choose Locale variable by dragging to the empty bar
now click the grey Locale box and in the popup enter parkedtime
change style to normal and back out to main widget screen
choose your background color
change text style normal to size 40dp
back out and click ok saving it
go into tasker
click on Car Set then disconnected hit the play button lower rh side
the widget on your screen should show the current time
tap on your new widget and then do the following
tick box "start another activity"
choose select activity or shortcut
click to shortcuts
go to tasker
choose shortcut
choose go car on task selection
save and back out
you are done!!
now when you hop out of your car the widget punches in your time of exit and location, when you tap the button it will navigate you back to your car